Greetings and a Few Questions From a Wannabe Seven Driver

[rider]

Hello gentlemen. I’m Henry; a long time lurker and a massive fan of Seven. I've watched possibly every YouTube video on 420R (my target). Read a ton of reviews. So far, read through past 5 years of discussions on this forum! My goal is to keep going back in time for a few more years of discussion!! Documented highlights of many reviews and problem areas. Have spent a lot of time spec'ing the car in the Configurator; many times over! So, I won't be asking any silly or noob questions even though I've seen a Seven in the wild just once!

 

There is one major issue I want to start with. This has come up a lot and many of you have done some mitigation. I'm trying to confirm the mitigation options and if they actually make a difference. 

 

The issue is cabin heat! The heat radiating from or felt in or due to:
    - Engine firewall
    - Transmission Tunnel
    - Footwell
    - From side-mounted exhaust
    - Full windshield and doors trapping the heat in the cabin
    
Mitigations done by some of you (sorry, I can't credit anyone since I didn't document who did what):
    - Powdercoat the header
    - Wrap parts of the header
        - I'm not sure if this is reliable as some bikers have tried wrapping exhausts and reported issues with moisture trapping, etc. (I'm a rider)
    - Heat Insulation materials on:
        - Bulkhead
        - Transmission tunnel
        - Firewall 
        - Footwell
        - Side panel along the exhaust
    - Reflective material on the footwell
    - Remove a part of Ali Sheeting (I don't know what this means!)
        - Remove the trapezoidal section of Ali plate that covers the rear of the transmission tunnel/diff area.  
        - Remove the rivets and leave it open.  Air now flows through the tunnel freely and the tubes are a lot cooler.
        (This sounds like a brilliant idea. If "you" are reading this, 'thanks'!)

 

Questions:
- Based on what I listed and your own experience, what are your thoughts?
- Is the heat manageable to a comfort level? 
    - It could get bit warm in stuck/stop-and-go traffic. But, not uncomfortably warm, let alone hot.
- Do listed mitigations (and others I'm not aware of) work?
- Or, am I being unrealistic? 

 

Appreciate your feedback and thoughts. Thanks.
 

[KnifeySpoony]

Of all the issues one can have with a 7, I wouldn't consider cockpit heat a "major" issue. There are many comfort/practicality/reliability/etc sacrifices made with owning a 7. Being a little hot inside is just another in a long list. The newer cars (ie all 420Rs) have insulation on the tunnel/footwells from the factory. I think most of the chatter on wrapping headers is on RHD duratec cars, as the exhaust puts more heat onto their driver's side. Please post a pic of your dream configurator spec...

[Croc]

 

Welcome Henry!

 

Heat is only an issue on the Caterham CSR260 or 620 models.  I melted my shoe sole in a 620R on track.  I also had to remove aluminum sheeting (undertray) and install vents for my CSR260 as I was burning my arms and legs on the cockpit chassis tubes.  

 

However, I also have a 420R that I keep in the UK for backroads and trackdays and I have never had a heat issue in that car.  

 

No special efforts needed for a 420 - it will be fine as is out of the box.

 

Cheers

mike

[IamScotticus]

I'm not any thermal engineer,  although I do have a thermal imager, I suspect that the felt heat  is not so much from hot air flow (which much of it is) but from radiated heat.  airflow and radiation shielding is required.  Even with that,  I have found it necessary to wear protective clothing, particularly where the knee and thigh enevitably rest against the tunnel.

in the end, this is a race car; creature comfort was not a consideration.  

Some things to consider are that the early 7s and perhaps the majority of 7s made by Lotus and early Caterham were RHD with left side exhaust.  Considering the average climate of northern European and UK markets, with lower atmosphere and road surface temperatures, cockpit heat may not have been a major complaint.   

The majority of sufferers seem to be the drivers with the exhaust on the drivers side.

In that the 420 is a RH exhaust and you are most likely considering a LHD 420, you may not have too much of a heat battle with the headers being opposite side of the feets.

 

It is not uncommon for drivers to need to wear the slimmest shoes they can find and racing shoes made with Nomex or fire resistant materials is an option.  Perhaps they should be a requirement. 

 

The seven you get will have its own particular set of niggles to work out.  Thats part of the fun of having one.  You get to work out solutions to problems quite frequently.  I appreciate the advance effort of research here.  The 7 is going to be what it is.  Like a motorcycle,  you sit on top of a machine that was barely designed to accommodate human beings, and you eventually learn to stop burning your legs,  or you get used to it 😉. 

 

I don't want to derail this thread, but my burning question is, why are you set on a 420?  That new car smell is nice, but there are 50 years of Caterhams to choose from.  You can get your training wheels for half the price.

 

 

 

Edited June 9, 2023 by IamScotticus

[panamericano]

Heat?  Try driving a Seven in 100 degree ambient weather.  I've never noticed much heat except in winter, when it is welcome.  The only hot spot was where my knee touches the tunnel.  Felt like a proper burn.  Fixed it with a pad glued to tunnel.  Welcome to the nut house.

[Vovchandr]

In NY I seek for means to get more heat into the cabin for most of the year. 

 

Taking off a pedal box on a Zetec helps A LOT to get your feet toasty

[Kitcat]

I measured the heat in my Xflow powered Cat down by my ankles on a 75 degree day:120degrees. On the passenger side it was 20 degrees cooler. So the observation that the right hand exhaust on the Duratec cars makes the driver’s side cooler seems apt (as opposed to the left side exhaust on all other versions, like my Xflow and my Zetec).

 

The biggest heat mitigation occurred when I swapped in a Brooklands screen for the standard barn door windshield. For whatever reason, the larger windshield trapped hot air and the Brooklands evacuated it immediately. 
 

I learned early on that it was hotter to wear shorts than long pants. The Bluejean fabric provided some insulation against the toasty transmission tunnel. And I promptly burned my bare leg on the exhaust pipe’s heat shield.

 

in many ways the Se7en induces so much sensory overload (fierce buffeting wind, intense noise, tooth rattling ride, vibration, minimal height, exhilaration, adrenaline, super car+  status among fellow motorists), that the heat becomes incidental.

 

Some have had success placing space age insulation on the bulkhead and around the pedal box. But all of the ideas you have listed help at least a bit.

[IamScotticus]

If I can fit it, l want to add a radiant pannel to the front of the pedal box, with an air gap in between to act as a radiant heat barrier. 

I have other bright ideas like paneling the bottom of the tunnel and having fan fins attached to the driveshaft to move air forward.  Bright ideas I haven't flushed out yet.  This might introduce a lot of dirt and dust.  Perhaps just boxing and blanking off the tunnel is better.

Edited June 10, 2023 by IamScotticus

[panamericano]

Don't be put off by Kitcat's remark.  "And I promptly burned my bare leg on the exhaust pipe’s heat shield."

 

I assure you that you will only do it once!

[BirkinBernie]

Welcome Henry!  I don't know about Minnesota or Ohio, but trust me, the heat is not incidental in Texas!  The transmission tunnel in the Birkin used to get hot enough to burn my leg.  When I had the drivetrain out some years back I installed insulation on the inside of the tunnel and it solved the problem.  I also sealed up the pedal box to stop hot air coming in through there.  I had the headers ceramic coated and I think that helped also but in any event they look nice.

 

BTW, on the subject of narrow shoes - I found wrestling shoes at a sporting goods store.  They are much cheaper than racing shoes, lightweight and no bigger than they need to be.  Comparable to racing shoes in comfort (as in not great for walking around) but in the car they are fine.

 

Happy Motoring!

[MV8]

Not pretty, but a .050" steel sheet over the top of the header with the back closed down the pan rail (open front and bottom) would help a lot for tunnel heat. It could attach to the header with standoffs or a chassis diagonal tube if equipped. Downside is the starter would get warmer if on the same side. Anything over the top along the head and down the back of the head would help to reduce the airflow into the tunnel.

 

Why steel? Steel is a much better heat shield than aluminum. The thermal conductivity of 3003 sheet is about 162 watts per kelvin per meter where sheet steel is around 45-50w/mk.  

Edited June 9, 2023 by MV8

[kayentaskier]

Welcome Henry,

if your target is a 420R, then I fully endorse Croc’s and Knifey’s comments. I live in the most SW corner of UT, temps are already in the 90s and in the Summer are above 100 for weeks at a time. I don’t drive my 420R here in July and August, but it’s not the heat generated by the car that prevents it, it’s the ambient temps that make it too hot to be outside in a open car. 
 

so now that we’ve put the heat issue to rest 😀 let’s hear the next concern so we can help you get into that 420R 

Jim

[rider]

21 hours ago, KnifeySpoony said:

......... The newer cars (ie all 420Rs) have insulation on the tunnel/footwells from the factory. I think most of the chatter on wrapping headers is on RHD duratec cars, as the exhaust puts more heat onto their driver's side. Please post a pic of your dream configurator spec...

 

Thanks KnifeySpoony. Great to hear 420 has added insulation. That's a relief. I'll ask about the possibility of doubling the insulation. Yes, will post the build specs and solicit feedback in a separate thread. 

 

 

17 hours ago, Croc said:

 

Welcome Henry!

 

Heat is only an issue on the Caterham CSR260 or 620 models.  I melted my shoe sole in a 620R on track. ......

However, I also have a 420R that I keep in the UK for backroads and trackdays and I have never had a heat issue in that car.  

 

No special efforts needed for a 420 - it will be fine as is out of the box.

....

 

Ouch! Getting your shoe sole melted sounds serious! I actually wanted 620S, just because....! But, I learned it only comes in RHD which is no-go for me. Hearing your feedback illustrates why 620 is a bad idea; more power, more heat! You might also have the heat-soak from supercharger. No Thanks! Good to know 420 works right out of the box. 

 

Thanks, Mike. 

 

 

14 hours ago, IamScotticus said:

.......... Even with that,  I have found it necessary to wear protective clothing, particularly where the knee and thigh enevitably rest against the tunnel.

....

In that the 420 is a RH exhaust and you are most likely considering a LHD 420, you may not have too much of a heat battle with the headers being opposite side of the feets.

 

It is not uncommon for drivers to need to wear the slimmest shoes they can find and racing shoes made with Nomex or fire resistant materials is an option.  Perhaps they should be a requirement. 

 

The seven you get will have its own particular set of niggles to work out.  Thats part of the fun of having one.  You get to work out solutions to problems quite frequently. ..........and you eventually learn to stop burning your legs,  or you get used to it 😉. 

 

I don't want to derail this thread, but my burning question is, why are you set on a 420?  That new car smell is nice, but there are 50 years of Caterhams to choose from.  You can get your training wheels for half the price.

 

 

 

 

Thanks for the details, IamScotticus. 

- I'm a shorts, t-shirt and sandals kinda guy when out for a spirited/casual driving. Prefer to leave the protective clothing to motorcycles! 

- Isn't the exhaust on the driver-side (left) on 420? If it is on the right, passenger-side, then, would the passenger feel the heat? 

- I'll be spec'ing SV chassis; so, I don't expect an issue in the pedal box. Street shoes/sandals should work; but, correct me if my understanding is incorrect.

- Ahh, the niggles! Yes, I've read through past five years of postings here, Piston Heads and few other places! I've a separate thread coming! 

- Why 420? Bit long-winded response: I'm in my mid-50s. ICE is going away soon; at least, ICE-only specs will be gone. I've very limited financial resources; wish I didn't blow up few opportunities along the way. But, working intensively to make up for them! In the meantime, going forward, I only want buy cars and motorcycles that I want to keep for good. I got just one shot. In a few years, we won't have cars that we care about buying! So, to me, 420 is at a good spot: highest spec NA model. If I flush out all the details and convinced that Seven is "go", then 420 is the only spec I want. I've a self-imposed limit of 3 or 4 cars and 2 motorcycles. So, will have to shuffle through and complete the cars list in 4-5 years.

 

 

 

13 hours ago, panamericano said:

Heat?  Try driving a Seven in 100 degree ambient weather.  I've never noticed much heat except in winter, when it is welcome.  The only hot spot was where my knee touches the tunnel.  Felt like a proper burn.  Fixed it with a pad glued to tunnel.  Welcome to the nut house.

 

I do like to rest the right knee on the tunnel when just cruising. Padding sounds like a good idea. Noted. Glad to hear heat isn't much of an issue in yours. And, yeah, Nut House is right....! Hope to get in there....! 

 

 

13 hours ago, Vovchandr said:

In NY I seek for means to get more heat into the cabin for most of the year. 

 

Taking off a pedal box on a Zetec helps A LOT to get your feet toasty

 

Interesting! That's a better problem to have, I suppose! Thanks. 

 

 

12 hours ago, Kitcat said:

I measured the heat in my Xflow powered Cat down by my ankles on a 75 degree day:120degrees. On the passenger side it was 20 degrees cooler. So the observation that the right hand exhaust on the Duratec cars makes the driver’s side cooler seems apt (as opposed to the left side exhaust on all other versions, like my Xflow and my Zetec).

...........
I learned early on that it was hotter to wear shorts than long pants. The Bluejean fabric provided some insulation against the toasty transmission tunnel. And I promptly burned my bare leg on the exhaust pipe’s heat shield.

 

in many ways the Se7en induces so much sensory overload (fierce buffeting wind, intense noise, tooth rattling ride, vibration, minimal height, exhilaration, adrenaline, super car+  status among fellow motorists), that the heat becomes incidental.

 

Some have had success placing space age insulation on the bulkhead and around the pedal box. But all of the ideas you have listed help at least a bit.

 

Thanks, Kitcat. As Mike and KnifeySpoony indicated, the observations you mentioned aren't applicable for 420, right? Getting burned isn't good! Yeah, you don't repeat that! Sensory Overload is one of the reasons I want a Seven! You can get a Porsche and call it a day! But, to make every drive an experience, we need a Seven or Atom or BAC Mono, et al. So, you have 2 or 3 Sevens? 

 

 

11 hours ago, IamScotticus said:

If I can fit it, J want to add a radiant pannel to the front of the pedal box, with an air gap in between to act as a radiant heat barrier. 

I have other bright ideas like paneling the bottom of the tunnel and having fan fins attached to the driveshaft to move air forward.  Bright ideas I haven't flushed out yet.  This might introduce a lot of dirt and dust.  Perhaps just boxing and blanking off the tunnel is better.

 

Interesting thoughts. Insulating the tunnel sounds more rewarding. KnifeySpoony mentioned above 420 comes with factory insulation. I'll ask about doubling or tripling, if spacing allows! 

 

 

11 hours ago, panamericano said:

Don't be put off by Kitcat's remark.  "And I promptly burned my bare leg on the exhaust pipe’s heat shield."

 

I assure you that you will only do it once!

 

I hear ya! If I manage to burn myself the second time, then, I would deserve it......! 

 

 

11 hours ago, BirkinBernie said:

......... When I had the drivetrain out some years back I installed insulation on the inside of the tunnel and it solved the problem.  I also sealed up the pedal box to stop hot air coming in through there.  I had the headers ceramic coated and I think that helped also but in any event they look nice.

 

BTW, on the subject of narrow shoes - I found wrestling shoes at a sporting goods store.  They are much cheaper than racing shoes, lightweight and no bigger than they need to be.  Comparable to racing shoes in comfort (as in not great for walking around) but in the car they are fine.

 

Happy Motoring!

 

 

Thanks, Bernie. I would follow the mitigations you've done. 420 is reportedly comes with insulation in tranny tunnel. The picture you shared, showing transmission tunnel? 

 

As for the shoes, I'll spec the SV chassis. Hoping I wouldn't have to worry about pedal spacing. 

 

 

10 hours ago, MV8 said:

Not pretty, but a .050" steel sheet over the top of the header with the back closed down the pan rail (open front and bottom) would help a lot for tunnel heat. It could attach to the header with standoffs or a chassis diagonal tube if equipped. Downside is the starter would get warmer if on the same side. Anything over the top along the head and down the back of the head would help to reduce the airflow into the tunnel.

 

Why steel? Steel is a much better heat shield than aluminum. The thermal conductivity of 3003 sheet is about 162 watts per kelvin per meter where sheet steel is around 45-50w/mk.  

 

Interesting idea, MV8. I'll add to the list for possible consideration. Thanks.

 

 

2 hours ago, kayentaskier said:

.......

if your target is a 420R, then I fully endorse Croc’s and Knifey’s comments. .........
so now that we’ve put the heat issue to rest 😀 let’s hear the next concern so we can help you get into that 420R 

Jim

 

Thanks, Jim. I'm super relieved to hear that 420 has insulation. Will explore about adding more insulation in other hot spots (pun unintended!) as well. Hope to make it as normal, with respect to cabin heat, as a standard Roadster. Need to make my girl comfortable to ride in!! Ahh, the next issue....! You saw through me! I've just one more major issue to discuss with you guys. It's for another thread!     I really do wanna get in a 420R. Based on everyone's feedback, I feel 40% better than yesterday! 

 

 

Here is my only audience/encounter with a Seven, at a local meet. Wish I met the owner! It was a love at first sight....!

 

 

 

[Croc]

 

For a newbie to this forum you multi-quote responses like a pro!  

 

I have always believed the 420 is the sweet spot of the range.  Most power that is realistically usable on the road and enough to make life good on the track.  The range topping cars of 620 and CSR (yes it is still available for order despite it being off-list) are just too powerful for the road.  The 620 is a monster on track as the torque effect on the rear wheels makes it a really tricky power delivery to manage - the deDion rear end is unable to handle 620 levels of power.  The deDion handles power up to around 250hp and then is outmatched.  Any higher than 250hp then really you need the CSR independent rear end to put the power down.

 

  

 

 

[BirkinBernie]

7 hours ago, rider said:

The picture you shared, showing transmission tunnel?

Yes, that pic is from the engine compartment looking back into the tunnel. 

[Kitcat]

Rider: I have had 3 se7ens in the last 15 years but am currently se7en less. My first, and favorite, was a ‘97 Xflow which I put 10K miles on.

 

It was replaced by a Duratec powered ‘09 Birkin. In someways it was superior to the Cat(better suspension) in some ways worse(interior was cramped, seats were torture). It’s poor build quality (due to the assembler, not the manufacturer) led to it’s relatively quick resale(to a member here who completely disassembled it and put it back together properly).

 

My final version was an SVT Zetec powered track only Caterham with a massive roll cage, 21 gallon FuelSafe tank etc. I sold it last year to another member here who bought it to race.

 

 I may buy yet another, who knows but, at age 76, it was getting to be a bit more than my aging body could handle:)!

 

I like your approach to this project, I am sure you will love a 420! I agree it is the ultimate blend of handling and power in a Caterham.

[BlakeJ]

My experience with 420 power in an SV chassis has been nothing short of fantastic. 

It starts and runs reliably, but absolutely rips on the street, and has enough legs to push the 1950's aero (or lack thereof) through, even at higher velocities, on track.

I'd echo what others have said about the LHD 420; it's the ambient air temps/humidity/sun that make it uncomfortable sometimes, not the heat from the car.

Finally, I, too, take drives in shorts and flips/slides/sandals, and the SV pedal box is accommodating of that footwear.

Enjoy the search!

[Christopher smith]

We did some work with Dow Chemical research guys( formerly Rohm and Haas ) who wanted to formulate insulating paint for industrial use. Seemed like an insulating layer of low thermal conductivity made a big difference in preventing injury to workers in factories who brushed up against pipes of very hot chemicals or steam. If you touch a metal pipe surface that is hot it transfers heat to your skin very fast. Their coating prevented burns by allowing you that fraction of a second to pull away. The secret additive was very small particle size hollow glass microspheres in their acrylic resin paint formulas. Might just be a good lightweight solution for metal skins in the driver and passenger areas and very easy to add to virtually any paint formula. Disclosure- I retired a few years ago

[rider]

16 hours ago, Croc said:

 

For a newbie to this forum you multi-quote responses like a pro!  

 

......... range topping cars of 620 and CSR (yes it is still available for order despite it being off-list) are just too powerful for the road.  The 620 is a monster on track as the torque effect on the rear wheels makes it a really tricky power delivery to manage - the deDion rear end is unable to handle 620 levels of power.  The deDion handles power up to around 250hp and then is outmatched.  Any higher than 250hp then really you need the CSR independent rear end to put the power down.

 

 

 

 

I've been around the block, Mike! 

 

Thanks for the details. Wonder why the CSR flopped. Is it because Seven Purists didn't entertain a "friendly" version?

 

 

15 hours ago, BirkinBernie said:

Yes, that pic is from the engine compartment looking back into the tunnel. 

 

Thanks. Will add to my list of possible mods. Will evaluate how the stock performs out of the box before making any change.

 

 

13 hours ago, Kitcat said:

..........

 I may buy yet another, who knows but, at age 76, it was getting to be a bit more than my aging body could handle:)!

 

I like your approach to this project, I am sure you will love a 420! I agree it is the ultimate blend of handling and power in a Caterham.

 

This (highlighted by me) is one of the data points in my consideration. From now, I'm letting my brain make a decision as opposed to heart, unlike in the past! ICE will be gone in a few years; or, the kind of cars we enthusiasts want to buy would be changed dramatically. So, no time to experiment. A 911 or Spyder can possibly be driven till the last day of your driving life. At a recent PCA (Porsche Club of America) event, I saw a gentleman with his mother in a wheelchair. At the end of the event, I saw her on the front passenger seat of his 911 and he was loading up the folded wheel chair in the back! Kid you not! Didn't see how he executed the whole process. That was impressive! I wanna be able to drive my Sportscar at ripe old age even if I were walking with a cane or walker! 

 

 

 

11 hours ago, BlakeJ said:

My experience with 420 power in an SV chassis has been nothing short of fantastic. 

It starts and runs reliably, ............

I'd echo what others have said about the LHD 420; it's the ambient air temps/humidity/sun that make it uncomfortable sometimes, not the heat from the car.

..........

 

Good to know; thanks. I'm still bit unclear about this unanswered question: does LHD (US-spec) car have exhaust on the passenger-side? Every picture I've seen, the exhaust is on the driver-side, whether LHD or RHD.

 

 

2 hours ago, Christopher smith said:

..........Might just be a good lightweight solution for metal skins in the driver and passenger areas and very easy to add to virtually any paint formula. Disclosure- I retired a few years ago

 

Thanks Christopher. Is there a commercially available product? Though it is now confirmed 420 has insulation for firewall and tranny tunnel, I still wanna explore options to possibly increase the insulation. Of course, I'll evaluate the stock, as-is spec before touching it.

 

 

[rider]

12 hours ago, BlakeJ said:

.............

It starts and runs reliably, .............

 

Forgot to address; actually, this comment deserves its own response! This is the first time I'm reading this phrase attributed to a Seven! Actually, it is very reassuring to hear the word "reliable" to describe the 420!